In a wireless communications system, in addition to a data signal, some known reference signals usually also need to be sent between user equipment and a base station, for example, a sounding reference signal (SRS), and are used for estimation of a radio channel status. The SRS is sent by the user equipment (UE) to the base station. The base station estimates an uplink channel status by using the received SRS, to perform resource scheduling based on the uplink channel status. In a time division duplex (TDD) system, because uplink and downlink channels have reciprocity, the SRS may further be used for estimation and measurement of a downlink channel.
In the prior art, an SRS may be sent in a periodic or aperiodic manner, and non-beamforming omnidirectional sending is used. Due to the omnidirectional sending, a base station of a surrounding cell may detect the sent SRS through listening. Consequently, interference to a neighboring cell is easily caused, and effectiveness of sending the SRS is reduced.